The given options include the names of animals. Let's analyze them:
1) **Tiger** - A big cat
2) **Jaguar** - A big cat
3) **Leopard** - A big cat
4) **Fox** - A member of the Canidae family (not a big cat)
The first three options belong to the **Felidae** (big cat) family, whereas **Fox** belongs to the **Canidae** (dog) family.
Thus, the odd one out is:
$\boxed{4}$ **Fox**